1. Field of the Invention
The present invention relates to a recording/reproducing head and a recording/reproducing apparatus incorporating the recording/reproducing head. More particularly, the present invention relates to a recording/reproducing head, a recording/reproducing apparatus, and a fabrication method thereof which are capable of higher-density recording than conventional hard disks and magneto-optical disk apparatuses.
2. Description of the Related Art
A hard disk drive (HDD) 1000 represented in FIG. 11 or a magneto-optical disk (MO) apparatus 2000 represented in FIG. 12 can record information signal in high density. These apparatuses include a magnetic head 1019 and a magneto-optical head 2020, respectively, as a recording/reproducing head.
When the magnetic head 1019 as shown in FIG. 11 is used to attempt to obtain high-density recording/reproducing which exceeds about 40 Gb/inch2, reproducing is feasible if a giant magnetoresistive (GMR) device 1014 is provided between shields 1015. In a structure of the magnetic head 1019 in which a surface of the GMR device 1014 is exposed, friction or noise occurs due to the GMR device 1014. When a tunnel type GMR (TMR) device is used instead of the GMR device 1014, a short circuit is likely to occur. Such a problem may be avoided by means of a so-called yoke-type head (not shown). In a conventional yoke-type head, however, a gap needs to be provided between the GMR device 1014 (or the TMR device) and the yoke, e.g., an insulating film or the like is provided in the gap. Such a gap, however, leads to a reduction in reproduced output. As to the recording, the width of a track needs to be on the order of less than a micron ( less than 0.3 xcexcm) while the film thickness of the magnetic head 1019 is held on the order of microns. This leads to an extraordinarily large aspect ratio and thus difficulty in processing. In the future, the length of a recorded bit in a recording medium is expected to be about 50 nm or less. In a recording medium having such a small bit size, thermal fluctuation must be taken into consideration. When an in-plane recording medium is used as a recording medium 1016, the coercive force of the recording medium 1016 needs to be significantly large. A recording magnet 1017 of the magnetic head 1019 is required to include a magnetic film having a saturated magnetization of about 2.5 T (tesla) or more so as to magnetize such a recording medium. At the present time, there exists substantially no such magnetic film.
On the other hand, in the magneto-optical head 2020 shown in FIG. 12, a recording medium 2016 is heated by laser light condensed by a condenser 2018 up to a temperature such that reversal of magnetization is likely to occur. In addition, a magnetization modulation technique using a magnetic head 2019 is utilized to record information into a bit which is smaller than the wavelength of laser light.
The magneto-optical head 2020 having the above-described structure shown in FIG. 12 can provide the same level of high-density recording as that of the HDD. Upon reproducing, however, the recorded bit needs to be enlarged up to as much as the wavelength of laser light. To this end, various methods have been proposed, but there still remains challenges insofar as practical use.
In such situations, a new recording/reproducing apparatus 3000 as shown in FIG. 13 has been proposed. The recording/reproducing apparatus 3000 includes a magneto-optical head 2020 and a GMR head 3019. Recording is performed using the magneto-optical head 2020. Reproducing is performed using the GMR head 3019. That is, two different heads are used for recording and reproducing, respectively. A recording medium 2016 for a magneto-optical disk is used as a recording medium.
On the other hand, in a recording/reproducing apparatus 4000 shown in FIG. 14, a magnetic head 1019 for HDD is used. A recording medium 4016 is irradiated by laser light at a side thereof opposite to the magnetic head 1019. This allows facilitation of reversal of magnetization in recording and facilitation of reading in reproducing.
However, the recording/reproducing apparatus 3000 shown in FIG. 13 requires two heads for recording and reproducing. There is a problem in that recording and reproducing are performed by the separate heads. Moreover, the recording/reproducing apparatus 4000 shown in FIG. 14 requires a servo technique to bring laser light to a region recorded on a recording medium. There is a problem in that the higher the density of recording, the greater the technical difficulty. In this case, there is also a significant problem with the processing of the small-width track in the HDD recording head as described above. In both the recording/reproducing apparatuses 3000 and 4000, the magnetic head and the laser irradiating section need to be provided on the upper and lower sides of the recording medium, respectively. For that reason, it is impossible to provide heads on the upper and lower sides of a disk and utilize both sides of the disk as recording surfaces. In terms of space-saving, such a structure is disadvantageous to the recording/reproducing apparatus.
Further, the magnetic head needs to be moved to a target position on a recording medium for recording or reproducing. In addition to the above-described problems, the higher the density of recording, the greater the difficulty in servo tracking when only one magnetic head driving section is provided in a conventional recording/reproducing apparatus.
According to a first aspect of the present invention, a magnetic head for reproducing a signal recorded on a recording medium, includes a substrate; a magnetic head core provided on the substrate, having a magnetic gap; and a first magnetoresistance device provided on the magnetic head core. The magnetic head core is provided in such a manner that a thickness direction of the magnetic head core around the magnetic gap is substantially the same as a track width direction of the recording medium.
In one embodiment of this invention, the magnetic head further includes a second magnetoresistance device provided on the magnetic head core. The first magnetoresistance device and the second magnetoresistance device are provided symmetrically with respect to the magnetic gap.
In one embodiment of this invention, the magnetic head further includes a coil. The coil is provided in such a manner that at least a portion of the magnetic head core is surrounded by the coil; and a signal is recorded onto the recording medium by a magnetic field from the magnetic head core generated by the coil.
In one embodiment of this invention, the first magnetoresistance device includes a first insulating layer provided on the magnetic head core; and a first pinned layer provided on a side opposite to the magnetic head core of the first insulating layer, in which a magnetization direction is not easily rotated in the first pinned layer. The magnetic head core includes a first soft magnetic layer provided at a position corresponding to the first insulating layer; and the first soft magnetic layer functions as a first free layer of the first magnetoresistance device, in which a magnetization direction is easily rotated in the first free layer.
In one embodiment of this invention, the second magnetoresistance device includes a second insulating layer provided on the magnetic head core; and a second pinned layer provided on a side opposite to the magnetic head core of the second insulating layer, in which a magnetization direction is not easily rotated in the second pinned layer. The magnetic head core includes a second soft magnetic layer provided at a position corresponding to the second insulating layer; and the second soft magnetic layer functions as a second free layer of the second magnetoresistance device, in which a magnetization direction is easily rotated in the second free layer.
In one embodiment of this invention, the first soft magnetic layer and the second soft magnetic layer are the same soft magnetic layer.
In one embodiment of this invention, the magnetic head further includes a laser condenser for heating a region of the recording medium in the vicinity of the magnetic gap.
In one embodiment of this invention, the substrate functions as the laser condenser.
In one embodiment of this invention, the laser condenser includes a diffraction optical device.
In one embodiment of this invention, the diffraction optical device is a Fresnel lens.
In one embodiment of this invention, the magnetic head core includes at least one of NiFe(xe2x80x94Co), CoFe, CoFeB and CoNbZr.
In one embodiment of this invention, the first pinned layer includes Co or CoFe pinned by PtMn, IrMn, or NiMn.
In one embodiment of this invention, the second pinned layer includes Co or CoFe pinned by PtMn, IrMn, or NiMn.
According to a second aspect of the present invention, a recording/reproducing apparatus includes a magnetic head according to the first aspect of the present invention; and a recording medium including a first magnetic layer.
In one embodiment of this invention, the first magnetic layer has a compensation temperature and a Curie temperature.
In one embodiment of this invention, the compensation temperature is in the range between room temperature and about 100xc2x0 C., and the Curie temperature is in the range between about 200xc2x0 C. and about 300xc2x0 C.
In one embodiment of this invention, the first magnetic layer includes a second magnetic layer for recording and a third magnetic layer for reproducing.
In one embodiment of this invention, the recording medium includes magnetic film micro dots magnetically separated from each other.
In one embodiment of this invention, the recording medium is a vertical magnetic storage medium.
In one embodiment of this invention, the recording medium is a disk.
In one embodiment of this invention, the recording medium is a tape.
In one embodiment of this invention, the recording/reproducing apparatus further includes a support for supporting the substrate; a first driving section for driving the support; and a second driving section for providing a movement of the magnetic head, provided on the substrate.
In one embodiment of this invention, the second driving section includes a thin film; and a movement of the magnetic head is provided by displacement of the thin film in a thickness direction thereof.
In one embodiment of this invention, the second driving section is driven by a piezoelectric system, an electrostatic system, or an electromagnetic system.
In one embodiment of this invention, the recording/reproducing apparatus further includes a plurality of the magnetic heads. The plurality of the magnetic heads are simultaneously driven by the first driving section.
In one embodiment of this invention, the first magnetic layer includes at least one of CoCr, CoPt, CoCrPt, CoCrTa, CoTaCrPt, FePt, TbFe, TbFeCo, and GdFeCo.
In one embodiment of this invention, the second magnetic layer includes TbFe or TbFeCo; and the third magnetic layer includes GdFeCo.
According to a third aspect of the present invention, a magnetic head for reproducing a signal recorded on a recording medium, includes a substrate; a magnetic head core provided on the substrate, having a magnetic gap; and a first magnetoresistance device provided on the magnetic head core. The first magnetoresistance device includes a first insulating layer provided on the magnetic head core; and a first pinned layer provided on a side opposite to the magnetic head core of the first insulating layer, in which a magnetization direction is not easily rotated in the first pinned layer. The magnetic head core includes a first soft magnetic layer provided at a position corresponding to the first insulating layer; and the first soft magnetic layer functions as a first free layer of the first magnetoresistance device, in which a magnetization direction is easily rotated in the first free layer.
In one embodiment of this invention, the magnetic head further includes a second magnetoresistance device provided on the magnetic head core. The second magnetoresistance device includes a second insulating layer provided on the magnetic head core; and a second pinned layer provided on a side opposite to the magnetic head core of the second insulating layer, in which a magnetization direction is not easily rotated in the second pinned layer. The magnetic head core includes a second soft magnetic layer provided at a position corresponding to the second insulating layer; and the second soft magnetic layer functions as a second free layer of the second magnetoresistance device, in which a magnetization direction is easily rotated in the second free layer.
In one embodiment of this invention, the first magnetoresistance device and the second magnetoresistance device are provided symmetrically with respect to the magnetic gap.
In one embodiment of this invention, the first soft magnetic layer and the second soft magnetic layer are the same soft magnetic layer.
In one embodiment of this invention, the magnetic head further includes a coil. The coil is provided in such a manner that at least a portion of the magnetic head core is surrounded by the coil; and a signal is recorded on the recording medium by a magnetic field from the magnetic head core generated by the coil.
In one embodiment of this invention, the magnetic head further includes a laser condenser for heating a region of the recording medium in the vicinity of the magnetic gap.
In one embodiment of this invention, the substrate functions as the laser condenser.
In one embodiment of this invention, the laser condenser includes a diffraction optical device.
In one embodiment of this invention, the diffraction optical device is a Fresnel lens.
In one embodiment of this invention, the magnetic head core includes at least one of NiFe(xe2x80x94Co), CoFe, CoFeB and CoNbZr.
In one embodiment of this invention, the first pinned layer includes Co or CoFe pinned by PtMn, IrMn, or NiMn.
In one embodiment of this invention, the second pinned layer includes Co or CoFe pinned by PtMn, IrMn, or NiMn.
According to a fourth aspect of the present invention, a recording/reproducing apparatus includes a magnetic head according to the third aspect of the present invention; and a recording medium comprising a first magnetic layer.
In one embodiment of this invention, the first magnetic layer has a compensation temperature and a Curie temperature.
In one embodiment of this invention, the compensation temperature is in the range between room temperature and about 100xc2x0 C., and the Curie temperature is in the range between about 200xc2x0 C. and about 300xc2x0 C.
In one embodiment of this invention, the first magnetic layer includes a second magnetic layer for recording and a third magnetic layer for reproducing.
In one embodiment of this invention, the recording medium includes magnetic film micro dots magnetically separated from each other.
In one embodiment of this invention, the recording medium is a vertical magnetic storage medium.
In one embodiment of this invention, the recording medium is a disk.
In one embodiment of this invention, the recording medium is a tape.
In one embodiment of this invention, the recording/reproducing apparatus further includes a support for supporting the substrate; a first driving section for driving the support; and a second driving section for providing a movement of the magnetic head, provided on the substrate.
In one embodiment of this invention, the second driving section includes a thin film; and a movement of the magnetic head is provided by displacement of the thin film in a thickness direction thereof.
In one embodiment of this invention, the second driving section is driven by a piezoelectric system, an electrostatic system, or an electromagnetic system.
In one embodiment of this invention, the recording/reproducing apparatus further includes a plurality of the magnetic heads. The plurality of the magnetic heads are simultaneously driven by the first driving section.
In one embodiment of this invention, the first magnetic layer includes at least one of CoCr, CoPt, CoCrPt, CoCrTa, CoTaCrPt, FePt, TbFe, TbFeCo, and GdFeCo.
In one embodiment of this invention, the second magnetic layer includes TbFe or TbFeCo; and the third magnetic layer includes GdFeCo.
According to a fifth aspect of a magnetic head for reproducing a signal recorded on a recording medium, includes a substrate; a magnetic head core provided on the substrate, having a magnetic gap; and a coil provided in such a manner that at least a portion of the magnetic head core is surrounded by the coil. A signal is recorded on the recording medium by a magnetic field from the magnetic head core generated by the coil; and the magnetic head core is provided in such a manner that a thickness direction of the magnetic head core around the magnetic gap is substantially the same as a track width direction of the recording medium.
According to a sixth aspect of the present invention, a recording/reproducing apparatus includes a first magnetic head for recording a signal onto a recording medium; and a second magnetic head for reproducing the signal recorded on the recording medium. The first magnetic head includes a first substrate; a first magnetic head core provided on the first substrate, having a first magnetic gap; and a coil provided in such a manner that at least a portion of the magnetic head core is surrounded by the coil. The first magnetic head core is provided in such a manner that a thickness direction of the first magnetic head core around the first magnetic gap is substantially the same as a track width direction of the recording medium. The second magnetic head includes a second substrate; a second magnetic head core provided on the second substrate, having a second magnetic gap; and a first magnetoresistance device provided on the second magnetic head core. The second magnetic head core is provided in such a manner that a thickness direction of the second magnetic head core around the second magnetic gap is substantially the same as a track width direction of the recording medium.
In one embodiment of this invention, the first substrate and the second substrate are the same substrate.
In one embodiment of this invention, the recording/reproducing apparatus further includes a second magnetoresistance device provided on the second magnetic head core. The first magnetoresistance device and the second magnetoresistance device are provided symmetrically with respect to the second magnetic gap.
According to a seventh aspect of the present invention, a recording/reproducing apparatus includes a first magnetic head for recording a signal onto a recording medium; and a second magnetic head for reproducing the signal recorded on the recording medium. The first magnetic head includes a first substrate; a first magnetic head core provided on the first substrate, having a first magnetic gap; and a coil provided in such a manner that at least a portion of the magnetic head core is surrounded by the coil. The first magnetic head core is provided in such a manner that a thickness direction of the first magnetic head core around the first magnetic gap is substantially the same as a track width direction of the recording medium. The second magnetic head includes a second substrate; a second magnetic head core provided on the second substrate, having a second magnetic gap; and a first magnetoresistance device provided on the second magnetic head core. The first magnetoresistance device includes an insulating layer provided on the second magnetic head core; and a pinned layer provided on a side opposite to the second magnetic head core of the insulating layer, in which a magnetization direction is not easily rotated in the pinned layer. The second magnetic head core includes a soft magnetic layer provided at a position corresponding to the second insulating layer; and the soft magnetic layer functions as a free layer of the first magnetoresistance device, in which a magnetization direction is easily rotated in the free layer.
In one embodiment of this invention, the first substrate and the second substrate are the same substrate.
In one embodiment of this invention, the recording/reproducing apparatus further includes a second magnetoresistance device provided on the second magnetic head core. The first magnetoresistance device and the second magnetoresistance device are provided symmetrically with respect to the second magnetic gap.
Thus, the invention described herein makes possible the advantages of providing hyper-density recording of about 100 Gb/inch2, and a recording/reproducing apparatus incorporating a magnetic head driving portion having a high-accuracy tracking performance in such hyper-density recording.
These and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.